Interfacial Stability of the In Situ Formed Copolymer

The evaluation of interfacial behavior of die in situ formed copolymer allows to indicate whether or not the copolymer stays at the interface as a frmction of time under quiescent or dynamic conditions. It is important to emphasize that the location of the copolymer at the interface is one of the important requirements for the interfacial adhesion between the blend phases. The in situ formed copolymer should not leave the interface upon further melt-processing. Polymer blends are very often subjected to different melt-processing operations for the fabrication of end-use products. 

The interfacial instability of the copolymer was also noticed in the reactively compatibilized Nylon 6/EPM/EPM-g-MA blends [59]. Prolonged mixing at a temperature of 250 °C in the mini-extruder led to shear induced coalescence of the dispersed EPM rubber particles giving rise to coarser domains (see Fig. 3.11). 

5 Effect of Reactive Blending on Crystallization of Blends Containing Crystallizable Components 

The crystallization behavior of a dispersed melt phase in an amorphous or semi-crystalline matrix phase has generated a lot of interest in recent years. In polymer blends in which the crystallizable phase is dispersed into tine droplets in the matrix, crystallization upon cooling from the melt can occur in several temperature intervals that are initiated at different undercoolings, often ending up with a crystallization at the homogeneous crystallization temperature T(.,hom- This phenomenon is often called fractionated crystallization [73, 74]. The phenomenon of delayed crystallization was directly related to the 

The fractionated crystallization behavior of PA6 in reactively compatibilized PA6/ PMMA blends, using SMA20 as compatibilizer, was analyzed by means of differential scaiming calorimetry [61]. The DSC results are presented in Fig. 3.17. As can be seen, only one crystallization peak is observed for the blend with 40 wt% PA6 where PA6 forms the matrix phase. It is interesting to note that several crystallization exotherms are 

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